ORIGINAL ARTICLE
OBSERVATIONS ON VASCULAR PATTERN OF CHORIONIC BLOOD VESSELS
OF PLACENTA
M. Yousuf Sarwar1, Nilesh Kumar2, Nawal Kishor Pandey3
HOW TO CITE THIS ARTICLE:
M Yousuf Sarwar, Nilesh Kumar, Nawal Kishor Pandey. “Observations on vascular pattern of chorionic blood vessels
of placenta”. Journal of Evolution of Medical and Dental Sciences 2013; Vol. 2, Issue 44, November 04; Page:
8650-8654.
ABSTRACT: BACKGROUND: Placenta is a choriodecidual structure develops during pregnancy
implanted on the uterine wall and carries vital functions. It is connected to the foetus through
umbilical cord. The branches of umbilical vessels that traverse along foetal surface of placenta are
referred as chorionic vessels. There are two different patterns of chorionic vessels – Dispersal and
Magistral. In the dispersal type, the umbilical vessels undergo successive divisions with gradually
diminishing caliber towards periphery while in magistral pattern the vessels traverse to the edge of
placenta without appreciable decrease in diameter of vessels. The present study has been done for
visualization of the pattern of chorionic vessels in placenta obtained from labour room of a tertiary
care hospital in eastern Bihar, India. MATERIALS AND METHODS: A total of one hundred and fifty
(150) fresh and intact placenta of full term pregnancies collected from Obstetrics & Gynaecology
department were included in the study. After washing with distilled water, removal of blood clots
were done with slight digital pressure applied over arteries and vein and later on by irrigation with
saline. The cut end of the umbilical cord was carefully visualized to identify the umbilical arteries
and vein. Dye was injected into umbilical vessels under normal physiological pressure and diameter
of chorionic blood vessels were taken at the center and periphery. Ultimately each vessel was
followed and examined to observe the dispersal and magistral pattern of chorionic blood vessels of
placenta. RESULTS AND CONCLUSION: Out of the total of one hundred and fifty (150) full term
placenta obtained and examined in the Anatomy department during the study period, 64% Dispersal
type & 36 % of Magistral type of arterial pattern of branching of chorionic vessels were observed.
Vein and its tributaries presented Dispersal pattern in 60% and Magistral pattern in 40%. There is a
significant relationship between the pattern of branching and weight of foetus. Reduction of
uteroplacental circulation results in foetal hypoxia & IUGR. The present study aims to observe the
incidence of vascular pattern of chorionic blood vessels of placenta.
KEYWORDS: Placentae, vascular pattern, chorionic blood vessels, dispersal, magistral.
INTRODUCTION: The placenta is a choriodecidual structure develops during pregnancy implanted
on the uterine wall near the fundus and carries important and vital functions & activities such as
respiration, nutrition, excretion, protection & hormone production.
The foetal part develop from chorionic sac & maternal part derived from endometrium.
Foetal surface of placenta is covered with smooth glistening membrane amnion which can be easily
stripped upto the umbilical cord. The surface of the chorion thus exposed is also smooth and
between its two layers run branches of umbilical vessels called chorionic vessels. These vessels are
responsive to vasoactive substance but morphologically functionally and histologically they are
peculiar.
Journal of Evolution of Medical and Dental Sciences/ Volume 2/ Issue 44/ November 04, 2013
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ORIGINAL ARTICLE
The placenta forms connections with the mother’s blood supply from which it supplies
oxygen and nutrients to the foetus and it also connects with the foetus’s blood supply from which it
removes wastes and returns them to the mother’s blood.
The chorionic artery always crosses over chorionic vein. Immediately just before or after
entering the chorionic plate the two umbilical arteries are joined by transverse connection. Initially
the arteries of human placenta are described being similar in their arrangement to the spokes of
wheel. In another study it is explained as a star like radiation and the vessels are described as falling
into primary, secondary and tertiary groups. But later on, the vascular pattern of placenta is
described as of two types – Magistral and Dispersal.
In the dispersal type – the umbilical vessels undergo successive division with gradually
diminishing caliber towards periphery, while in magistral type the umbilical vessels is characterized
by the arteries that traverse to the edge of placenta without appreciable decrease in diameter of
vessels.
In another study there is a significant relationship between the pattern of branching, number
of primary divisions of arteries and vein and weight of the foetus. Reduction of uteroplacenta
circulation results in fetal hypoxia & IUGR. The study on the vascular pattern of chorionic blood
vessels of placenta still lagging behind. The present study aims to observe the incidence of vascular
pattern of chorionic blood vessels of placenta in Indian population.
MATERIALS & METHODS: One hundred fifty (150) fresh and intact placenta were collected from
labour room of the department of Obstetrics & Gynaecology, Katihar Medical College & Hospital,
Katihar, Bihar, India, over a span of two years.
All the placenta, after washing with distilled water, fresh specimen were placed in the tray.
The cord was cut 6 cm from its attachment to the placenta. From the chorionic surface, the amniotic
membrane was removed. Removal of blood clots were done initially with slight digital pressure
applied over arteries and vein from peripheral parts of placenta towards the attachment of cord to
the placenta and later on by irrigation with saline. For the infusion of colored material in placental
vessels the cut end of the umbilical cord was carefully visualized to identify the umbilical arteries
and vein. Both of the umbilical arteries were injected with Methylene blue 15 – 20 ml to make them
clearly visible blue colored artery and their branches. 0.5% 20 – 30 ml Eosin was injected in
umbilical vein to visualize stem of the umbilical vein.
Each vessel was followed and examined to count its dispersal and magistral pattern. In the
dispersal type, the two arteries divide dichotomously several times into a number of smaller vessels,
rapidly diminishing in caliber. In the magistral type the two arteries were extend almost to the
margin of placenta before diminution in their caliber.
Diameter of chorionic blood vessel was taken by vernier caliper at the site of insertion of
umbilical cord (c) and at the periphery (p). It was categorized into two groups on the following
criteria if the ratio of diameter of chorionic blood vessels of placenta at the periphery and at the
center (p/c) is half or less than half it is categorized into dispersal type, more than half then it is
categorized into magistral type.
Mean and standard deviation of all observations were calculated. Mean is the arithematic
means of all observations. Standard deviation is the measure of variation. It is defined as root –
mean – square deviation.
Journal of Evolution of Medical and Dental Sciences/ Volume 2/ Issue 44/ November 04, 2013
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ORIGINAL ARTICLE
OBSERVATION: One hundred fifty (150) fresh full term placenta were obtained for study and
examined. Diameters of chorionic blood vessels of placenta were measured after washing and
injecting the dye under normal physiological pressure. Two types of vascular pattern were observed
– Dispersal and Magistral. Diameter of chorionic blood vessels showed decreasing trend from center
to periphery in dispersal pattern while in the magistral pattern diameter of chorionic blood vessels
was almost same throughout its whole extent.
Arterial pattern of branching of chorionic vessels was of dispersal type in 64% and magistral
type in 36%. The maximum number of primary divisions of arteries ranged between 4-6 in Dispersal
pattern with the mean of 4.62 and standard deviation of 1.39 & maximum number of primary
divisions of artery in Magistral pattern ranged between 3-6 with the mean of 4.11 and standard
deviation of 1.80 [Table 1].
Vein and its tributaries presented Dispersal pattern in 60% and Magistral pattern in 40%. In
dispersal pattern maximum number of tributaries in vein ranged from 3-6 with the mean of 4.90 and
standard deviation of 1.45. Maximum number of tributaries in vein is Magistral pattern ranged from
3-5 with mean of 4.75 and standard deviation of 1.31 [Table 2].
Sl.no
1
2
3
4
5
6
7
8
9
Dispersal type
Magistral type
Number of
Primary Division No. of Placenta Percentage No. of Placenta Percentage
1
03
02.0
03
02.0
2
03
02.0
06
04.0
3
06
04.0
15
10.0
4
36
24.0
09
06.0
5
27
18.0
09
06.0
6
12
08.0
06
04.0
7
06
04.0
03
02.0
8
03
02.0
03
02.0
Total
96
64%
54
36%
Table 1: Number of primary Division of Arteries
Dispersal:- Mean – 4.62 ± S.D – 1.39
Magistral:- Mean – 4.11 ± S.D – 1.80
Sl.no
1
2
3
4
5
6
7
8
9
Dispersal type
Magistral type
Number of
Primary Division No. of Placenta Percentage No. of Placenta Percentage
1
00
00.0
00
00.0
2
00
00.0
00
00.0
3
15
10.0
09
06.0
4
27
18.0
21
14.0
5
21
14.0
15
10.0
6
12
08.0
09
06.0
7
09
06.0
03
02.0
8
06
04.0
03
02.0
Total
90
60%
60
40%
Table 2: Number of primary Division of Veins
Dispersal:- Mean – 4.90 ± S.D – 1.45
Magistral:- Mean – 4.75 ± S.D – 1.31
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ORIGINAL ARTICLE
DISCUSSION AND CONCLUSION: During intrauterine existence the foetus depends upon the
placenta as its Lungs, Liver and Kidney. Despite its major role in human development, the study of
placenta has lagged behind that of foetus. A number of anatomists and embryologist worked through
1980s to provide some basic knowledge (Cunnigham et al.).
The vascular pattern of chorionic blood vessels of placenta is described as of two typesMagistral and dispersal (Schordania). In the dispersal pattern umbilical vessels undergo successive
divisions and rapidly diminish in caliber while in magistral pattern umbilical vessels give side
branches and the caliber of vessels is almost equal upto periphery. The vascular character of foetal
placental vasculature is already recognizable at 12th week of pregnancy (Bacsich & Crawford). In the
present study dispersal pattern showed successive divisions of umbilical vessels with decreasing
caliber from center to periphery while the magistral pattern showed fewer divisions of blood vessels
with appreciably no decrease in diameter from centre to periphery.
The pattern of branching of blood vessel is dispersal (with radiating spoke like arrangement)
in 81 cases and magistral (with marginal cord attachment and vascular channels) in 86 cases
(Bhargava & Raja). The incidence of dispersal pattern is 63% and that of magistral pattern is 37%
(Cunnigham et al.). In the present study the incidence of dispersal pattern is 64% and magistral
pattern is 36% in arterial pattern of branching of chorionic vessels which is very close to the above
findings.
It is noted that certain anatomic characteristic such as pattern of branching, number of
primary divisions of arteries and veins are determined at an earlier stage of development. After
determination of these characteristics, the parameters differentiate in response to functional
demands, stress and strain in subsequent developmental periods (Bhargava & Raja; Schordania;
Bacsich & Crawford). In another study it is observed that there is significant relationship between
patterns of branching, number of primary divisions of arteries and weight of foetus.
In the present series number of primary divisions of arteries usually lies between 3-6 both in
magistral and dispersal pattern. The observations in the present series reveal the pattern of vein and
arteries in the present series did not necessarily correlate with each other. Out of 150 placenta
dispersal type is 64% and magistral type is 36% in arterial pattern of branching while vein and
tributaries presented dispersal pattern in 60% and magistral in 40%. Present study gives broad
range of information regarding vascular pattern of chorionic blood vessels of placenta.
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AUTHORS:
1. M. Yousuf Sarwar
2. Nilesh Kumar
3. Nawal Kishor Pandey
PARTICULARS OF CONTRIBUTORS:
1. Assistant Professor, Department of Anatomy,
Katihar Medical College, Katihar, Bihar, India.
2. Assistant Professor, Department of Anatomy,
Katihar Medical College, Katihar, Bihar, India.
3. Professor, Department of Anatomy, Katihar
Medical College, Katihar, Bihar, India.
NAME ADDRESS EMAIL ID OF THE
CORRESPONDING AUTHOR:
Dr. M. Yousuf Sarwar,
Department of Anatomy,
Katihar Medical College,
Katihar – 854 105, Bihar, India.
Email – drmysarwar@gmail.com
Date of Submission: 10/10/2013.
Date of Peer Review: 11/10/2013.
Date of Acceptance: 25/10/2013.
Date of Publishing: 31/10/2013
Journal of Evolution of Medical and Dental Sciences/ Volume 2/ Issue 44/ November 04, 2013
Page 8654